Off-circuit tap-changer with wedge-shaped contact structure

Abstract

The invention discloses an off-circuit tap-changer of a wedge-shaped contact structure. The off-circuit tap-changer comprises an upper supporting seat and a lower supporting seat, a main shaft penetrates between the upper supporting seat and the lower supporting seat; one end of the main shaft is connected with the operating mechanism; the main shaft is connected with a gear mechanism; the outputend of the gear mechanism is connected with a grooved wheel mechanism; the grooved wheel of the grooved wheel mechanism is hollowly sleeved on the main shaft, and is connected with the moving contact;the moving contact support is provided with moving contact assemblies which are slidably connected with the moving contact support; and static contact columns configured with the moving contact assemblies are correspondingly arranged at the circumference of the moving contact assemblies. The off-circuit tap-changer of the wedge-shaped contact structure is characterized in that: a crank is arranged on the main shaft, the crank is connected with the moving contact support pieces of the moving contact assemblies through the connecting rod of the crank mechanism, so that the moving contact assemblies can intermittently rotate along with the grooved wheel mechanism and can also slide and stretch along with the crank mechanism in the radial direction. During gear shifting, the moving contact does not rub with the static contact columns, so that the gear shifting torque of the switch is small, a plating layer of the contact is protected from being damaged, and transformer oil is prevented from being polluted by metal powder generated by contact friction.

Description

technical field [0001] The invention relates to the technical field of an off-excitation tap changer, in particular to an off-excitation tap changer with a wedge-shaped contact structure. Background technique [0002] The wedge-shaped contact structure drum-shaped off-excitation tap changer is a product designed for the technology introduced from the Soviet Union to China in the 1980s. This off-excitation tap-changer has been used for many years. Due to the high precision requirements for manufacturing and the limited number of gears Most of the defects such as , operation and so on are gradually eliminated by other structural switches, so that the structural switches are no longer produced in China. The main defects are: ①The circumferential direction of the switch can only be divided equally by 6 static contact columns, that is, the 6 static contact columns are evenly distributed at 60°, and only 5 tap positions can be achieved, which does not meet the requirements of mult...

AI Technical Summary

Problems solved by technology

[0002] The wedge-shaped contact structure drum-shaped off-excitation tap changer is a product designed for the technology introduced from the Soviet Union to China in the 1980s. This off-excitation tap-changer has been used for many years. Due to the high precision requirements for manufacturing and the limited number of gears Most of the defects such as , operation and so on are gradually eliminated by other structural switches, so that the structural switches are no longer produced in China

The main defects are: ①The circumferential direction of the switch can only be divided equally by 6 static contact columns, that is, the 6 static contact columns are evenly distributed at 60°, and only 5 tap positions can be achieved, which does not meet the requirements of multi-tap position switches

②It can only be rotated in one direction to change gears. After the gear is adjusted (such as 3rd gear), it cannot be reversed to the original gear 3rd gear. It can only be reached after changing a tap cycle in the original direction.

③During the whole process of shifting gears, there is no feel and sound of the moving contacts being in place, and it is impossible to intuitively determine whether the switch is in place

Every time you change a gear, you need to rotate more than 300° and then reverse to the card position. There are often accidents where the gear is not in place and the switch is burned.

④Although the wedge-shaped contact is reliable, the original guide and crankshaft are all sliding friction, resulting in a large shift torque, which makes it impossible to use this structure for high-current switches

However, there are the following problems in the operation process: ① When shifting gears, the moving contact slides and rubs along the surface of the static contact column, which increases the wear of the contact, and is particularly easy to wear off the coating on the surface of the dynamic and static contact columns. Metal powder also contaminates transformer oil

②During the whole process of shifting, there is no feel and sound of the moving contact in place, and it is difficult to determine whether the moving contact of the switch is in place from the mechanism

③When the movable contact is a top-to-top type or wedge-shaped contact with a large angle, the angle between the contact tangent points of the movable contact is large. In order to ensure the contact pressure, it is necessary to increase the pressure of the contact spring, thereby increasing The switching torque is reduced, resulting in a particularly large switching torque, especially it cannot meet the requirements of small switching torque when the number of contacts of high-current switches on the market is large.

④The moving contact is supported by two pin shafts. When shifting gears, the moving contact needs to move radially and circumferentially at the same time. The moving contact is easily constrained by the two pin shafts and has poor contact.

⑤The switch has no mechanical limit position. If the limit position is exceeded, the position in contact with the switch contact will be inconsistent with the indicated position.

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